1. Technical Field
The present invention relates to a card with a display function which utilizes a thermosensitive type display device provided in the body of the card to display information relating to the card, and in particular relates to a card with a display function wherein the rewriting of the display information is possible from within the body of the card.
2. Background Art
In conventional cards with a display function, as device for displaying a portion of the data stored on widely used magnetic cards, for example, there has been developed and employed a device with a display section provided on the card surface wherein magnetism is used to set iron powder or the like into a desired shape (xe2x80x9cVISMACxe2x80x9d from The Nippon Signal Co., Ltd. is a commercial example of such a product), and a device wherein reversible thermal recording (thermal printing) is carried out on the card surface.
Furthermore, in the case of non-contact cards, which are receiving considerable attention because of the superior performance offered in terms of security and environmental resistance (refer to, for example, Japanese Unexamined Patent Publication No. 10-105669, Japanese Unexamined Patent Publication No. 10-107710, and Japanese Unexamined Patent Publication No. 10-154216), then as considerably cheaper and thinner cards have become available, and the practical applications thereof have increased, there has been a growing demand for an ability to display stored data and the like on such cards, in the same manner as is possible with the aforementioned contact type magnetic cards.
Examples of non-contact cards with a display function which have been proposed include those disclosed in Japanese Unexamined Patent Publication No. 10-93484 and Japanese Unexamined Patent Publication No. 10-154215. The technology disclosed in the above patent publications, in both cases, relies on the use of a display device which utilizes a (ferroelectric) liquid crystal and which is provided on a non-contact card in order to display stored data. Furthermore, in a known non-contact card disclosed in Japanese Unexamined Patent Publication No. 7-125483, technique has been proposed wherein a rewrite layer which enables the rewriting of data and comprises a thermal reversible recording layer, a composite membrane layer, or a magnetic display layer is provided on the card is provided on the card, to display stored data on such a card.
However with the display systems, such as VISMA or thermal printing, applied to conventional cards with a display function as described above, because the card itself does not have a function for rewriting display information, an external rewriting apparatus or the like must be used to rewrite the display information on the card. In such cases however, the possibility arises of the display information that has been rewritten by the external apparatus no longer corresponding to the stored data on the card, and the identification of such a correspondence relationship between the display information and the stored data is difficult. Consequently, cases of misuse have occasionally been reported where, in order to prevent the display information from changing, a piece of tape, for example, is stuck over the display information portion of the card.
Furthermore, in the case of the conventional cards described above which use a liquid crystal display or the like, because of the comparatively high cost of liquid crystals, the cards are expensive. Moreover there is also a limit on how thin the cards can be made. As a result, it is very difficult with current technology to produce a thin, low cost card with a display function as being demanded.
Moreover in a conventional non-contact card with a display function which is provided with a rewrite layer for enabling the rewriting of display information, the device for rewriting the display of the rewrite layer is not provided within the card, and so the rewriting of the rewrite layer must be carried out using an external rewriting apparatus. Because such rewriting apparatus require a mechanical card transport system and a recording device such as a thermal head, not only is one of the advantages of a non-contact system lost, namely the ability to process data without a card transport system, but furthermore the cost of the card system increases. In addition, when a transport system is used in the rewriting of the display, the direction in which a card is inserted into the rewriting apparatus needs to be either identified or restricted in some manner.
The present invention takes the above factors into consideration, with an object of providing a thin, low cost card with a display function in which the card display information is able to be rewritten within the card itself, without the use of an external rewriting apparatus.
In order to achieve the above object, according to the present invention, there is provided a card with a display function having a thermosensitive section which varies in state on sensing thermal energy, and comprising a display device within the body of the card for displaying information in accordance with the state of the thermosensitive section, wherein the display device incorporates a heating section for generating thermal energy, and the state of the thermosensitive section varies on sensing the thermal energy from the heating section.
With such a construction, the state of the thermosensitive section can be varied by the thermal energy generated from the heating section, enabling the rewriting of the display information to be conducted solely within the body of the card.
The construction may be such that the card with a display function described above comprises a memory for storing data, and a control device for controlling the writing of data to, and reading of data from, the memory, and the heating section generates thermal energy in accordance with a display command output from the control device.
With such a construction, then in the case of a card such as an IC card, which is provided with a function for storing data internally, information corresponding to the stored data can be displayed automatically by the display device.
Furthermore, another possible construction may be such that the card with a display function comprises a communication device for carrying out communication with an external card processing apparatus, and the heating section generates thermal energy in accordance with a display command sent from the card processing apparatus via the communication device.
With such a construction, thermal energy is emitted from the heating section in accordance with a display command from the card processing apparatus.
Yet another possible construction may be such that the card with a display function combines the constructions described above, that is, comprises a memory for storing data, a control device for controlling the writing of data to, and reading of data from, the memory, and a communication device for carrying out communication with an external card processing apparatus, and the heating section generates thermal energy in accordance with either a display command sent from the card processing apparatus via the communication device, or a display command output from the control device.
With such a construction, the communication of commands and data and the like between the card and the card processing apparatus is conducted via the communication device, and the execution of processing for the writing of data to, and reading of data from, the memory, as well as the rewriting of the display information in accordance with the processing, is carried out within the card.
As a specific example of the type of communication device in a card with a display function described above, communication with the card processing apparatus may be conducted in a non-contact manner. Thereby, a display function can be realized with a simple construction for a so-called non-contact card.
As another specific example of a communication device, communication with the card processing apparatus may be conducted via a contact element. Thereby, a display function can be realized with a simple construction for a so-called contact card.
The communication device of the contact type cards described above may conduct data communication with a card processing apparatus in a non-contact manner. With such a construction, data communication with the card processing apparatus is conducted in a non-contact manner, without having to pass through a contact element, thereby enabling the reliability of the card.
The card with a display function described above may comprise an electrical power supply device for operating each section of the card using electrical power supplied from the card processing apparatus. Furthermore, the electrical power supply device may also be constructed so as to obtain electrical power from an electromagnetic induction wave transmitted from the card processing apparatus. Moreover, a heating electrical power supply device for obtaining electrical power for supply to the heating section from the card processing apparatus may also be provided. As a result, an unpowered card with a display function, which does not require batteries or the like in the body of the card, can be realized.
Furthermore, with the card with a display function described above, the heating section may comprise a plurality of heating elements, and a selection section may be provided for selecting a heating element or heating elements from amongst the plurality of heating elements for generating thermal energy in accordance with a display command. Moreover, a heating control section may also be provided for controlling the amount of thermal energy generated by the heating section in accordance with a display command.
With such a construction, by selectively heating specific heating elements of the heating section, or controlling the amount of heating, in accordance with a display command sent from the card processing apparatus or the control device, information of various types can be displayed by the variation in state of the thermosensitive section.
Furthermore, the thermosensitive section may also incorporate a reversible thermosensitive material, the state of which would vary reversibly on sensing thermal energy. The reversible thermosensitive material may be either a color development type or a light scattering type. Such a thermosensitive section would enable the repeated renewal of the display information in accordance with rewriting of stored data.